1. Technical Field
The present invention relates to the field of integrated circuit layout and design. More specifically, the present invention relates to a design process and structure for providing input/output components on an integrated circuit.
2. Description of the Related Art
The development of the technology for the fabrication and design of integrated circuits has allowed designers to place ever increasing functionality onto a smaller area of integrated circuits. This makes the surface area of an integrated circuit extremely valuable. A component of integrated circuits that occupies a relatively large area are the input/output (I/O) modules.
I/O Modules provide the attachment point for electrical bonding to the integrated circuit die. I/O modules generally consist of a bond pad, an electrostatic discharge protection device and I/O buffer circuitry. The core circuitry is generally composed of very small devices. These devices are fast and densely packed, but fragile. The I/O modules provide protection to the core circuitry as well as a connection point for getting signals on and off of the integrated circuit. Because they must provide this protection function, I/O modules use relatively large devices and occupy a disproportionate area on the integrated circuit die.
I/O modules are generally positioned on the periphery of the integrated circuit die. This makes the process of bonding to the bond pads easier and helps buffer the core circuitry from the physical stresses of cutting the die from the semiconductor wafer during manufacturing. The area occupied by the I/O modules is determined by the height (distance from the edge of the die to interior edge of the I/O modules) of the I/O modules. The remaining portion of the chip is available for core circuitry. Designers are always looking for ways to put more functionality onto an integrated circuit. Because of this, it is desirable to use the minimum area necessary for I/O modules to provide as much area as possible for the core circuitry.